1. Field of the Invention
The present general inventive concept relates to a photoresist composition, a method of forming a pattern using the photoresist composition, and an inkjet print head using the photoresist composition, and more particularly, to a photoresist composition providing a polymerization product which resists formation of cracks therein due to an inner stress in a pattern formed using a mixture of an oxetane-containing compound and an oxirane-containing compound, a method of forming a pattern using the photoresist composition, and an inkjet print head using the photoresist composition.
2. Description of the Related Art
Photholithography which is performed to form various kinds of patterns uses photoresists. A photoresist is a light-sensitive resin which has a varying solubility with respect to a developer when exposed to light so that an image corresponding to an exposure pattern can be obtained. Photoresists are categorized into a positive photoresist which is a type of photoresist in which a portion of the photoresist that is exposed to light becomes soluble to a developer and the exposed portion is removed in a developing process to obtain a desired pattern, and a negative photoresist which is a type of photoresist in which a portion of the photoresist that is exposed to light becomes substantially insoluble to a developer and the unexposed portion of the photoresist is removed in a developing process to obtain a desired pattern.
To obtain a structure having a predetermined pattern, the photoresist is coated on a substrate together with a solvent and then an exposure process and a developing process are performed thereon. For example, Korea Laid-open Publication No. 2004-0037858 discloses a method of forming a pattern using polycarbomethylsilane derivative for photoresist.
A pattern forming technique using photoresist can be applied in a wide range of applications in most technical fields, including inkjet print heads or micro electro mechanical systems (MEMS).
An inkjet printer is a device that forms an image of a predetermined color by ejecting small droplets from inkjet print head to a desired site of a to-be-printed medium. According to an ejection mechanism of ink droplet, inkjet print heads can be categorized into a thermal operation-type inkjet print head that uses a thermal source to generate bubbles of ink and ejects ink droplet by an expansion force of the generated bubbles, and a piezo-electric operation-type inkjet print head that uses a piezo-electric material and ejects ink droplet by a pressure that is applied to ink due to deformation of the piezo-electric material used. Inkjet print heads include a chamber layer and/or a nozzle layer, and the chamber and nozzle layers should be formed in such a way that ink is easily ejected and the chamber and nozzle layers are effectively adhered to a substrate supporting the chamber and nozzle layers. Furthermore, the chamber layer and/or nozzle layer of the thermal operation-type inkjet print heads requires excellent heat tolerance.
Meanwhile, a MEMS switch, which is the most common type of radio frequency (RF) devices using a MEMS technology, requires various sacrificial layers having predetermined patterns in the fabrication process.
There is a need to develop a photoresist composition suitable for a fabrication process of inkjet print head or a MEMS switch photoresist composition.
Conventionally, an epoxy resin is used in a process of fabricating inkjet print head or MEMS switch. The epoxy resin possesses excellent mechanical properties but its polymerization product cracks when exposed to an inner stress.
Therefore, to prevent formation of cracks, there is a need to develop a novel photoresist composition which can hinder formation of cracks due to an inner stress.